A semiconductor integrated circuit is subjected to an electrical test to see whether or not it is produced in accordance with a specification. This type of electrical test is conducted by using an electrical connecting apparatus such as a probe card, a probe block, a probe unit and the like, provided with a plurality of probes (i.e., contacts) to be pressed individually against electrodes of the integrated circuits. This type of electrical connecting apparatus is used to electrically connect the electrodes of the integrated circuit and a tester.
The probes for use in this type of electrical connecting apparatus include needle-type one produced from a conductive thin metallic wire, a plate-like blade-type one, a probe element-type one using a probe element with projected electrodes formed in wiring on one surface of an electrical insulating sheet (film), and so forth.
The blade-type probe includes a single plate-type one produced from a electrical conductive metal plate, and a laminated-type one for which exposure and etching to a photoresist, and plating to the etched part are performed once or more.
Any types of the probes are cantilevered on a support member such as a wiring board, with the front ends (i.e., tips) of tip portions (i.e., contact portions) pressed against the electrodes of the integrated circuit. When the tips are pressed against the electrodes of the integrated circuit, an overdrive acts on the probes, which are curved by elastic deformation.
There is a blade-type probe which is Z-shaped and comprises: a first and a second arm portions extending in the back and forth direction at a distance in the vertical direction; a first and a second joint portions connecting the first and the second arm portions to each other at their front end and rear end portions; a tip portion continuous to the lower side of the first joint portion; and an attaching portion continuous to the upper side of the second joint portion (Patent Document 1).
There is another blade-type probe which comprises: a first and a second arm portions extending in the back and forth direction at a distance in the vertical direction; a joint portion connecting the first and the second arm portions to each other at their rear end portions; a tip portion continuous to the lower side of the front end portion of the first joint portion; and an attaching portion continuous to the upper side of the front end portion of the second joint portion (Patent Document 2).
In the conventional probe, the attaching portion is attached to a suitable support member and is supported like a cantilever on the support member, and the tip is pressed against the electrode of the integrated circuit in that state. Thereby, an overdrive acts on the probe, which is then curved at its first and second arm portions by elastic deformation.
Patent Document 1: Japanese Patent Appln. PD No. 7-115110
Patent Document 2: Japanese Patent Appln. PD No. 2003-57264
The probe used for an electrical test of the integrated circuit is generally assembled into an electrical connecting apparatus such as a probe card, assembled into the tester, and thereafter, in a state of being illuminated from the tip side (integrated circuit side), photographed from the tip side by an area sensor such as a video camera, and an output signal of the area sensor undergoes image processing, to obtain the position of the tip relative to the tester or the electrode of the integrated circuit and positioned for determining its coordinate position.
In a recent integrated circuit, the size of an electrode itself and an arrangement pitch of electrodes tend to be smaller. The size of an electrode itself and an arrangement pitch of probes (especially, tips) to be used in such an integrated circuit must be also made smaller.
In the conventional probe, however, the underside of the pedestal portion is a flat plane orthogonal to the vertical direction, so that, if the tip is made small, it is unavoidable for a reflected light from the underside of the pedestal portion to enter the area sensor, and the reflected light from the underside of the pedestal portion cannot be identified. As a result, according to the conventional probe, the position of the tip relative to the tester or the electrode of the integrated circuit cannot be accurately determined.
Unless the tip position can be determined accurately as mentioned above, accurate positioning between the tester or the integrated circuit and the probe cannot be made, so that the tip of the probe is not pressed against the electrode of the integrated circuit. Consequently, it is not possible to conduct a correct electrical test.